ith the shores; our fertile plains are formed from the
ruins of the mountains; and those travelling materials are still pursued
by the moving water, and propelled along the inclined surface of the
earth[1] These moveable materials, delivered into the sea, cannot, for
a long continuance, rest upon the shore; for, by the agitation of the
winds, the tides and currents, every moveable thing is carried
farther and farther along the shelving bottom of the sea, towards the
unfathomable regions of the ocean.

[Note 1: M. de Luc, in his second letter to me, published in the Monthly
Review for 1790, says, "You ought to have proved that both gravel and
sand are carried from our continents to the sea; which, on the contrary,
I shall prove not to be the case." He then endeavours to prove his
assertion, by observing, that, in certain places where there is not
either sufficient declivity in the surface, or force in the running
water, gravel and sand are made to rest, and do not travel to the sea.
This surely is a fact to which I most readily assent; but, on the other
hand, I hope he will acknowledge, that, where there is sufficient
declivity in the surface, or force in the running water, sand, gravel,
and stones, are travelled upon the land, and are thus carried into the
sea--at last. This is all that my theory requires, and this is what I
believe will be admitted, without any farther proof on my part.]

If the vegetable soil is thus constantly removed from the surface of the
land, and if its place is thus to be supplied from the dissolution of
the solid earth, as here represented, we may perceive an end to this
beautiful machine; an end, arising from no error in its constitution as
a world, but from that destructibility of its land which is so necessary
in the system of the globe, in the economy of life and vegetation.

The immense time necessarily required for this total destruction of
the land, must not be opposed to that view of future events, which is
indicated by the surest facts, and most approved principles. Time, which
measures every thing in our idea, and is often deficient to our schemes,
is to nature endless and as nothing; it cannot limit that by which alone
it had existence; and, as the natural course of time, which to us seems
infinite, cannot be bounded by any operation that may have an end, the
progress of things upon this globe, that is, the course of nature,
cannot be limited by time, which must proceed in a contin